PHOSPHORUS-CONTAINING THERMOPLASTIC POLYESTER AND PHOSPHORUS-CONTAINING HEAT-SHRINKABLE TUBE MADE THEREFROM

摘要

A thermoplastic polyester is disclosed to contain a flame retardant and has an intrinsic viscosity between 0.70 and 1.10 dL/g, and for making the disclosed polyester a phosphorus-containing flame retardant is bound onto the molecular chains of the matrix polymer through modification of the molecular structure of the matrix polymer; wherein the disclosed polyester due to having a content of phosphorus between 3,000 and 30,000 ppm based on the weight of the polyester is suitable for making phosphorus-containing heat-shrinkable tubes that possess permanently flame-retardant properties, has a UL94 VTM-2 flame-retardant rating, and even meets the requirements for UL94 VTM-0 flame-retardant rating.

主权项

1. A phosphorus-containing thermoplastic polyester for use in making phosphorus-containing heat-shrinkable tubes having a UL94 VTM-2 flame-retardant rating, characterized in that the polyester is, having an intrinsic viscosity between 0.70 and 1.10 dL/g and containing a content of phosphorus between 3000 and 30,000 ppm based on a weight of the polyester, obtained by having pure terephthalic acid (PTA) or ester thereof react with ethylene glycol (EG) at a molar ratio (EG/PTA) of EG to PTA ranging between 1.0 and 2.0 to undergo a direct esterification process and a polycondensation process successively in the presence of a phosphorus-containing flame retardant added before the end of esterification; wherein the phosphorus-containing flame retardant is one or a combination of phosphorus-containing compounds selected from those having the chemical structure formulas of (I), (II), (III), (IV), (V), (VI), (VII) or (VIII) as followed: